1. Field of the Invention
The present invention relates to a corneal surgical apparatus for incising the cornea of an eye of a patient in a layered form at the time of a keratorefrative surgery or the like.
2. Description of the Related Art
In recent years, attention has been focused on a LASIK surgery (laser in situ keratomileusis) for the keratorefractive surgery wherein a flap is formed by incising a portion with a thickness of about 0.15 mm from the corneal epithelium to the corneal stroma with a part of the cornea remaining connected like a hinge, ablating the corneal stroma in a refractive correction amount by an excimer laser light, and returning the flap to its original position. In the LASIK surgery, a corneal surgical apparatus called microkeratome is used for incising the cornea in a layered form.
As a corneal surgical apparatus, one comprising a suction ring to be vacuum-fixed to a part of the cornea from a corneal ring portion to the surface of the conjunctiva, a cornea applanating member for applanating the cornea flatly, and a blade movable toward the hinge while being oscillated laterally so as to incise the flattened cornea into a layer form with a substantially uniform thickness, is known.
As a mechanism for the blade lateral oscillation, as shown in FIG. 13A, one comprising a rotation shaft 301 to be rotated by a driving device such as a motor, an eccentric pin 302 provided at the tip end of the shaft 301, a transmitting member 304 having a vertical groove 303 to be engaged with the pin 302 is proposed. The transmitting member 304 having a blade 300 fixed thereto is held movably in the lateral direction (right and left direction, that is, the direction perpendicular to the paper surface in FIG. 13) in a receiving groove formed in a blade holder 305 and a holder block 306. When the shaft 301 is rotated by drive of the motor, force is applied on the transmitting member 304 in the lateral direction according to the circumferential movement (circular motion) of the pin 302 engaged with the vertical groove 303. Accordingly, the transmitting member 304 oscillated laterally (moved in the right and left direction), and further, the blade 300 fixed to the transmitting member 304 is oscillated laterally as well.
However, according to the conventional mechanism, as shown in FIG. 13B, by the circumferential movement of the pin 302, not only the force in the lateral direction but also force in the vertical direction (up and down direction) is applied to the transmitting member 304. That is, since the pin 302 with the circumferential movement comes in contact with the wall of the vertical groove 303 so that force is applied on the transmitting member 304 in the vertical direction due to the friction force generated by the contact, the transmitting member 304 is oscillated laterally while being moved-also in the vertical direction. Therefore, if the shaft 301 is rotated at a high speed, the transmitting member 304 and the blade 300 generate vertical oscillation (up and down movement) called xe2x80x9crampagexe2x80x9d in addition to the lateral oscillation.
The xe2x80x9crampagexe2x80x9d hinders stable incision as well as generates a loss in terms of the efficiency of converting the rotational motion to the lateral oscillation. Moreover, since the corner part of the transmitting member 304 is contacted with a blade holder 305 and the holder block 306 frequently so as to be applied with a large force, the parts are worn out rapidly so that the life cycle thereof is shortened.
The displacement amount of the transmitting member 304 to be displaced vertically and laterally (in the up and down, and right and left directions) according to the circumferential movement of the pin 302 corresponds to the eccentric amount of the pin 302, but as to the vertical direction, since the transmitting member 304 is held by the blade holder 305 and the holder block 306 in the vertical direction, the transmitting member 304 (and the blade 300) is displaced (vertical oscillation) for the gap with respect to each member. Therefore, accurate production without a gap among the transmitting member 304, the blade holder 305 and the holder block 306 would prevent the vertical oscillation (that is, xe2x80x9crampagexe2x80x9d), however, much labor is required for meeting the demand particularly in mass production so as to increase the cost.
In view of the above-mentioned problems, an object of the present invention is to provide a corneal surgical apparatus capable of forming a good flap by preventing xe2x80x9crampagexe2x80x9d of a blade. Effects of the apparatus include efficient generation of lateral oscillation, restraint of the cost rise according to high accuracy of the mechanism, and high durability.
In order to solve the above-mentioned problems, the invention is characterized by the following features.
(1) A corneal surgical apparatus for incising a cornea of a patient""s eye in a layered form, comprising:
a suction ring unit, having a circular opening, that is to be vacuum-fixed onto a peripheral part of the cornea;
a rotatable shaft;
an eccentric pin projecting from a distal end of the shaft, the eccentric pin being located at a position offset from a rotational central axis of the shaft; and
a cutting unit movable in an incising direction above the suction ring unit, the cutting unit including:
cornea applanating means that applanates the cornea within the opening into a substantially flat form;
a blade that incises the cornea;
a first oscillation transmitting member having a part with which the eccentric pin is engaged;
a second oscillation transmitting member having a part with which a part of the first oscillation transmitting member is engaged; and
a holder that holds the first and second oscillation transmitting members to be movable in a lateral direction which is perpendicular to the rotational central axis of the shaft,
wherein movement of the second oscillation transmitting member in the lateral direction causes the blade to be moved in the same direction.
(2) A corneal surgical apparatus according to (1), wherein the blade is fixed to the second oscillation transmitting member.
(3) A corneal surgical apparatus according to (1), wherein the first oscillation transmitting member includes:
a vertical groove elongating in a direction perpendicular to both of the lateral direction and the rotational central axis of the shaft, the eccentric pin being engaged with the vertical groove; and
a pin part extending toward the second oscillation transmitting member;
wherein the second oscillation transmitting member includes a pin receiving part with which the pin part of the first oscillation transmitting member is engaged.
(4) A corneal surgical apparatus according to (1), wherein the holder holds the first and second oscillation transmitting member to be movable linearly in the lateral direction.
(5) A corneal surgical apparatus according to (1), wherein the first oscillation transmitting member includes a shaft part rotatable about an axis different in location from the rotational central axis of the shaft, the shaft part having at least one of a recess and a protrusion, and
wherein the holder includes a bearing part that rotatably supports the shaft part and that has a part with which the shaft part is engaged, the holder holding the first oscillation transmitting member to be rockable in the lateral direction.
(6) A corneal surgical apparatus according to (5), wherein the holder holds the second oscillation transmitting member to be movable linearly in the lateral direction.
(7) A corneal surgical apparatus according to (5), wherein the shaft part of the first oscillation transmitting member includes two shaft parts respectively located on an upper part and a lower part of the first oscillation transmitting member, and
wherein the bearing part includes two bearing parts respectively supporting the two shaft parts.
(8) A corneal surgical apparatus according to (5), wherein the shaft part of the first oscillation transmitting member is rotatable about an axis intersecting the rotational central axis of the shaft.
(9) A corneal surgical apparatus according to (8), wherein the rotational central axis of the shaft part of the first oscillation transmitting member intersects the rotational central axis of the shaft perpendicularly.
(10) A corneal surgical apparatus according to (9), wherein the eccentric pin is provided on an axis passing through an intersecting point at which the rotational central axis of the shaft part intersects the rotational central axis of the shaft.
(11) A corneal surgical apparatus according to (1), wherein the eccentric pin is provided on an axis non-perpendicularly intersecting the rotational central axis of the shaft.
(12) A corneal surgical apparatus according to (1), further comprising:
a drive unit that rotates the shaft.
(13) A corneal surgical apparatus according to (1), further comprising:
a drive unit that moves the cutting unit in the incising direction.
(14) A corneal surgical apparatus for incising a cornea of a patient""s eye in a layered form, comprising:
a suction ring unit, having a circular opening, that is to be vacuum-fixed onto a peripheral part of the cornea;
a rotatable shaft;
an eccentric pin projecting from a distal end of the shaft, the eccentric pin being located at a position offset from a rotational central axis of the shaft; and
a cutting unit movable in an incising direction above the suction ring unit, the cutting unit including:
cornea applanating means that applanates the cornea within the opening into a substantially flat form;
a blade that incises the cornea;
a rock transmitting member having a part with which the eccentric pin is engaged and a shaft part rotatable about an axis different in location from the rotational central axis of the shaft, the shaft part having at least one of a recess and a protrusion; and
a holder that holds the rock transmitting members to be rockable in a lateral direction which is perpendicular to the rotational central axis of the shaft, the holder having a bearing part rotatably supporting the shaft part of the rock transmitting member, the bearing part having a part with which the shaft part is engaged,
wherein movement of the rock transmitting member in the lateral direction causes the blade to be moved in the same direction.
(15) A corneal surgical apparatus according to (14), wherein the shaft part of the rock transmitting member includes two shaft parts respectively located on an upper part and a lower part of the rock transmitting member, and
wherein the bearing part includes two bearing parts respectively supporting the two shaft parts.
(16) A corneal surgical apparatus according to (14), wherein the shaft part of the rock transmitting member is rotatable about an axis intersecting the rotational central axis of the shaft.
(17) A corneal surgical apparatus according to (16), wherein the rotational central axis of the shaft part of the rock transmitting member perpendicularly intersects the rotational central axis of the shaft.
(18) A corneal surgical apparatus according to (17), wherein the eccentric pin is provided on an axis passing through an intersecting point at which the rotational central axis of the shaft part intersects the rotational central axis of the shaft.
(19) A corneal surgical apparatus according to (14), wherein the eccentric pin is provided on an axis which non-perpendicularly intersects the rotational central axis of the shaft.
(20) A corneal surgical apparatus according-to (14), further comprising:
a drive unit that rotates the shaft.
(21) A corneal surgical apparatus according to (14), further comprising:
a drive unit that moves the cutting unit in the incising direction.
(22) A corneal surgical apparatus for incising a cornea of a patient""s eye in a layered form, comprising:
a suction ring unit, having a circular opening, that is to be vacuum-fixed onto a peripheral part of the cornea;
a rotatable shaft;
an eccentric pin projecting from a distal end of the shaft, the eccentric pin being provided on an axis non-parallel to and non-perpendicular to a rotational central axis of the shaft; and
a cutting unit movable in an incising direction above the suction ring unit, the cutting unit including:
cornea applanating means that applanates the cornea within the opening into a substantially flat form;
a blade that incises the cornea;
a transmitting member having a part with which the eccentric pin is engaged; and
a holder that holds the transmitting member to be movable in a lateral direction which is perpendicular to the rotational central axis of the shaft,
wherein movement of the transmitting member in the lateral direction causes the blade to be moved in the same direction.
(23) A corneal surgical apparatus according to (22), wherein the eccentric pin is provided on an axis that nonperpendicularly intersects the rotational central axis of the shaft.
(24) A corneal surgical apparatus according to (22), further comprising:
a drive unit that rotates the shaft.
(25) A corneal surgical apparatus according to (22), further comprising:
a drive unit that moves the cutting unit in the incising direction.
The present disclosure relates to the subject matter contained in Japanese patent application Nos. Hei. 11-55696 (filed on Mar. 3, 1999) and Hei. 11-90337 (filed on Mar. 31, 1999), which are expressly incorporated herein by reference in their entireties.